In general, pockets capable of accommodating in-cabin items are often installed below surfaces of door trims of sedan type, hardtop type, and other type automobiles, or below surfaces of luggage side trims in one-box cars (i.e., vans). A conventional door pocket installed in the door trim will be described. As shown in FIG. 8, a pocket opening 1a is provided in a lower side of the surface of a door trim 1, and a pocket back cover 2 made of a resin molding is fitted to an inner side surface of the pocket opening 1a to constitute the door pocket of the door trim 1.
In order to fit this pocket back cover 2 to the inner surface of the door trim 1, fitting pieces 3 are disposed at appropriate intervals along both side edges and a lower edge of the pocket back cover 2, and fitting holes 3a are provided in these fitting pieces 3.
A fitting boss 4 protrudes from the inner surface of the door trim 1 corresponding to the fitting hole 3a of the fitting piece 3. As shown in FIG. 9, the fitting boss 4 is inserted into the fitting hole 3a, and is affixed by fitting a fixing piece 4a, such as a push-on fixing piece, to one side of the fitting boss 4.
Thus, in each door pocket, a back surface, both side surfaces, and a bottom surface are formed in the pocket back cover 2, and a front surface is formed in the door trim 1. When an open door is closed by a vehicle occupant, for example, a front edge part of the pocket opening 1a is often grasped by hand to close the door. In this situation, the door is less rigid since the front wall of the door pocket is thin-walled, and it is easy to induce deformation. Upon grasping the door, therefore, the feeling is not good, i.e., not substantial, because of the lack of rigidity.
In order to solve these problems, a case-shaped pocket cover 5 with a top surface opened is used in a manner as shown in FIG. 10. This pocket cover 5 has an opening 5a substantially equal to the pocket opening 1a provided in the door trim 1, and a flange 5b is provided on a rear edge of the opening 5a. Fitting holes 5c are opened in the flange 5b, a fitting piece 5d is disposed on both sides of the pocket cover 5, and fitting holes 5c are provided in the fitting pieces 5d. 
A plurality of bosses 6 protrude from an upper part of the front surface of the pocket cover 5 at appropriate intervals along the horizontal direction.
A boss 7 for ultrasonic welding protrudes from an inner surface of the door trim 1 corresponding to the fitting hole 5c, and a hollow cylindrical boss 8 protrudes from the door trim 1 corresponding to the boss 6 of the pocket cover 5.
Regarding an attaching structure of the pocket cover 5, the boss 7 for ultrasonic welding of the door trim 1 is inserted into the fitting hole 5c of the pocket cover 5 as shown in FIG. 11, and welded and affixed thereto. The pocket cover 5 is firmly affixed to the inner side surface of the pocket opening 1a of the door trim 1 by attaching iron clips 9, fitted to the boss 6 disposed on the front wall of the pocket cover 5, to an inner circumferential surface of the boss 8 of the door trim 1.
However, the following problems still occur even in a case of using the above-described case-shaped pocket cover 5.
Since the iron clips 9 are used in conjunction with the door trim 1 and the pocket cover 5 (which are resin moldings), recycling of the door trim 1 cannot be performed unless the iron clips 9 are removed. Surplus recycle steps are thus required, the cost for the iron clips 9 is increased, and thereby the product cost increases.
In addition, when the pocket cover 5 is fitted to the inner surface of the door trim 1, locking claws 9a of the iron clips 9 are advanced while moving along the inner surface of the boss 8. Thus, during the fitting, no “click stop” feeling can be detected to ensure that the fitting has been effected. Thus, reliable fitting of the pocket cover 5 cannot be easily checked, and a problem of insufficient fitting reliability also exists.
Accordingly, an object of the present invention is to provide a pocket structure disposed on the interior trim such as the door trim, that provides a good, i.e., substantial, grasp when the front edge part of the pocket opening is grasped, that is less easily deformed in an interior component using a pocket cover made of a case-shaped resin molding, and that is also easily recyclable, inexpensive, and capable of increasing the assembly reliability of the pocket cover.